Art of preparing relief printing-surfaces.



NITED STATES PATENT OFFICE.

RUDOLF WIDMANN, OF MUNICH, GERMANY.

ART OF PREPARING RELlEF PRINTING-SURFACES.

SEEGLFIQAIION forming part of Letters Patent No. 682,581, datedSeptember 10, 1901.

Original application filed July 22, 1899, Serial No. 724,877. Dividedand this application filed October 25, 1900. $erial No. 34,377. (Nospecimens.)

To all whom it may coiicern:

Be it known that I, RUDOLF WIDMANN, a citizen of Bavaria, Germany,residing at Munich, in the Empire of Germany, have invented certain newand useful Improvements in the Art of Preparing ReliefPrinting-Surfaces, (this being a division of my application filed July22, 1899, Serial No. 724,877,) and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

This invention relates to the art of preparing plates which may be usedfor typographically printing and which present the design in relief.

The object of the invention is to produce a plate of this characterwhich shall combine a half-tone effect with the necessary contrast ofhigh light and intense shade, thereby securing an artistic effect of ahigh order and which shall also enable the artist in executing hisdesign to usev such materials as will permit him to work withoutrestraint and in the same manner as when using the ordinary artistsmaterials. In my application for Letters Patent, Serial No. 724,877,filed July 22, 1899, of which this is a divisional application, I havedescribed a method for this purpose whereby the design is executeddirectly upon the plate from which the printing-surface is to beprepared by first applying to said plate an acid-resisting grain andthen drawing the design thereon with acid-resisting chalk or crayon, theamount of shadow or light being governed by the amount of pressureexerted upon the crayon and by the same upon the grained plate. Theplate is then etched, and thereupon the acid resist, comprising thecrayon and the acid-resisting grain, is removed by any usual or suitablemeans, whereupon the printing-plate is complete. The present inventiondiffers from that in my aforesaid application in that the design is notexecuted on the grained plate, but upon a suitably-preparedtransfer-sheet, and in that I employ a liquid or semiliquid fatty paintwhich is to be applied by means of a brush instead of a fatty crayon orchalk.

I will now give a detailed description of what I consider the preferredmethod of carrying out my invention.

A suitable sheet of paper or film material, which may be transparent ornot, according to the requirements of each individual case, is coated onthe surface to be painted on with a suitable painting-ground of asomewhat sticky material, such as a mixture of albumen and isinglass,and the same is then tanned by immersing it in a tan'nin solution orequivalent treatment. On the background so produced the original designor painting is executed in a liquid or semiliquid black fatty color orpaint, which should be soluble in oil and adapted to dry quickly. Thiscolor is applied to the ground by means of a brush, similarly to watercolors, sepia, or india-ink painting. The painting-ground prepared asabove has the property and the object of preventing the oil which may beused as a dissolving medium from penetrating and spreading over thepaper and of allowing the fatty color or paint to adhere to but not topenetrate into the fibers of the paper. This grounding, moreover, hasthe property of slowly dissolving in water. All of these properties arenecessary to produce the best effects under my invention, as will appearhereinafter. With the use of the materials above set forth I may apply apaint one or more times to portions already painted on, according todemand and as may be desired, or the paint may be completely removed atsuch portions where it is desired to change or correct the execution ofthe design, and such places may be left open or again painted over,according to the requirements of the case. The painting or design soexecuted is then allowed to dry.

The printing-plate upon which the design is to be transferred isprepared as follows: A plate to be etched, preferably a zinc plate, isprovided with an acid-resisting grain on its smooth flat surface bydusting over the same a comminuted resist, such as resin-pow- 9 der, inthe manner well known. The particles of this powder are caused to adhereto the plate by heating the same to such an extent that the resinousparticles will melt sufficiently to adhere to the surface. The design infatty color prepared as above described is now transferred upon thisgrained plate by laying the sheet of paper with the design facing thegrained surface of the plate upon the same and then causing the same toadhere to the plate by a strong and even pressure in a manner which iswell-known in the art of etching plates which are not grained. Thepainted sheet of paper is thereby'caused to firmly adhere to the grainof the plate. The painted sheet is thereupon moistened, whereby theadhesive background orgrounding will slow ly dissolve and permit thepaper to be pulled off from the plate, leaving the entire fatty designupon the grain and between the grains upon the plate in masses whichcorrespond exactly to the light, shade, and half-tone of the design. Inother words, the design has been completely transferred to the plate,with this difference that the light tones have been broken up or finelysubdivided by the acid-resisting grain. Each individual particle of theresinous powder is surrounded by fatty substances, the amount of thesame being governed by the thickness of the fatty layer at each portionof the design executed. The dark surfaces on the design are transferredas dense patches of fatty substances. The lighter or half tones appearbroken up into stipples, whose size correspond to the degree ofhalf-tone. Those portions where the painting-ground was left entirelyfree or unpainted leave the interstices between the grain in theiroriginal condition. High lights may be very readily attained on anyportion of the picture by suitable instruments well known in the art.Corrections may be readily and accurately carried out by employing afatty crayon, such as lithographic crayon. After the plate has beenprepared in this manner it is directly etched by immersing it orflooding it with dilute acid in the well-known manner, whereupon theacid-resist, comprising the resinous grain, as well as the fatty design,may be removed in any usual or desired way by using the ordinarysolvents or thelike. All those portions which have been covered by theacid-resisting grain and the fatty color will appear in relief, sincethey were not attacked by the acid. The portions of the plate which werenot covered by such resist, on the other hand,will be etched and presentrecesses which will form the white or unprinted portion after theprinting.

Instead of executing the transfer design in fatty color upon thetransfer paper by hand the same may manifestly be produced by printing.Thus, for example, I may utilize a proof from any printing-plate whichappears in black and White, in lines or in dots, by first going over thesame with a brush and changing the same to a half-tone picture.

It is to be noted that this invention is applicable to the preparationof relief-plates for decorative purposes, as well as for the manufactureof relief printing-plates.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is

1. The process of producing relief printingsurfaces which consists intransferring a design in resisting ink or paint to a plate provided witha grain of resisting material and then etching theplate.

2. The process of producing relief printingsurfaces which consists intransferring a painted or half-tone design made with an etching-resistto a plate provided with a resisting-grain, and then etching the plate.

3. The process of producing relief printingsurfaces which consists intransferring a painted or half-tone design made with an etching-resistto a plate provided witlra resisting-grain, then etching the plate, andre' moving the resisting-grain and design.

4. The process of producing relief printingsurfaces which consists inexecuting a fatty design upon a sheet or film provided with a solubleadhesive grounding and providing a plate to be etched with aresisting-grain, then transferring said design to the grained plate, andthen etching. I

5. In the art of preparing relief printingplates, the method ofpreparing a transfersheet which consists in coating a sheet or film witha mixture of albumen and isinglass and then painting a design thereon infatty paint.

6. In the art of producing relief printingsurfaces the process whichconsists in coating a sheet of paper or the like with a mixture ofalbumen and isinglass, then painting thereon a design in fatty paint,then transferring such design upon a plate provided with a resingrainand finally etching the plate.

7. In the art of producing relief printingsurfaces the process whichconsists in coating a sheet of paper or the like with a mixture ofalbumen and isinglass, then painting thereon a design in fatty paint,then transferring such design upon a plate provided with a resingrainand finally etching the plate and removing the resin-grain and fattypaint.

In testimony whereof I affix my signature in presence of two witnesses.

RUDOLF WIDMANN.

Witnesses:

GEORGE J. BURNS, LUDWIG WIDMANN.

